Spider
Extermination and Control (North America):All spiders
encountered in North American yards, forests, trees, and landscaping
make their living preying on insects. Most of the insects
that spiders prey on are harmful to us, our grasses, shrubs, trees, and
gardens. Without spiders, therefore, we would be overrun with insects and our lives would be much less enjoyable.

Since spiders are such beneficial organisms, rather than taking steps to exterminate them, we
should instead do our best to keep them alive. Still, two kinds
of spiders--black widows and recluse spiders--pose a clear danger to man
and should be exterminated in or on residential or commercial
structures, or in barns used to house cows, horses or sheep,
whenever they are found. Others need to be controlled because their
habits make them problematic in unusual ways. Under those circumstances,
it may be best to spider-proof the areas we want to keep spiders out of,
and exterminate those that outwit our spider-proofing endeavors.

FIRST THE BAD NEWS: Traditional residual pesticides, in the form
of sprays, dusts, or granular baits, are not effective at exterminating
spiders unless brought into direct contact with them. Spiders hunt live
prey exclusively and show no interest in inert baits. Further, a
spider's body mass is elevated, so only the tips of each leg--the miniscule tarsus--touches
the ground or the spider's web, where residual pesticides might
otherwise intoxicate them.
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